Circuit-interrupting device



Nov. 4, 1930. J, W, WENS 1,780,684

CIRCUIT INTERRUPTING DEVICE Filed Feb. 4, 1928 Inventor Joseph W. Owens,

His Attorneg.

Patented Nov. 4, 1930 JOSEPH W. OWENS, 0F SCHENECTAIDY, NEW YORK,ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORKCIRCUIT-INTERRUPT'ING DEVICE Applicationfiled February 4, 1928. SerialNo. 251,987.

This invention relates to circuit interrupting devices and moreparticularly to a detachable arc barrier arrangement for multi poleelectric switches and the like.

The principal object of the present inven tion is to provide an improvedmounting for the arc barriers that will enable the barriers to bemounted and demounted without the use of tools. In this way the barriersmay be easily removed to permit access to the arcing contacts of thecircuit interrupter for wiring or inspection and repair.

The improved arc barriers of the present invention are particularlyadvantageous in multipole electric switches which are mounted within aninclosing casing. With such switches it is desirable that the arcbarriers located between the adj acent. poles of the switch be readilyremovable without necessitating the removal of the switch mechanism fromthe inclosing casing. Heretofore it has been the common practice tosecure the arc barriersto the base upon which the switch contacts aremounted bymeans of screws or other fastenings accessible only from theback of the base. I-Ience with such mounting of the arc barriers it isnecessary to unwire and remove the entire switch mechanism from theinclosing casing before the arc barriers may be removed. Moreover, thearc barriers must be secured in place before the switch mechanism ismounted in the inclosing casing and thus prevent free and convenientaccess to the switch contacts during wiring or inspection and repairoperations. In addition the metallic screw fastenings for the arcbarriers tend to weaken the insulating properties and cause the arc tostrike through the barriers.

The present invention enables the arc barriers to be readily mountedbetween the adjacent poles of the switch after the base with the switchmechanism thereon is mounted within the inclosing casing and the wiringoperation is entirely completed. Likewise, the arc barriers may bereadily removed and replaced at any time it is necessary to repair orinspect the switch parts. In addition, with the present invention thearc barriers may be moulded of arc-resisting material, such for example,as an asbestos compound, having a unitary structure provided withlocking projections whereby the arc barriers are mounted or supported intheir operative position between the poles of the switch mechanismwithout any metallic fastenings whatever.

In carrying the present invention into effect in a preferred form thearc barriers are formed preferably of moulded arc-resisting material andprovided with projecting locking keys adapted to cooperate with suitablelocking holes in the base upon which the switch mechanism is mounted.The arrangement is such that the locking keys upon the arc barriers maybe inserted in the locking holes formed in the base and the barriermoved laterally with respect to the base to bring the keys into lockingengagement with the keyholes. Upon reverse lateral movement of the arcbarriers the locking engagement is released to permit removal of the arcbarriers. In addition, the arc barriers preferably have formed integraltherewith projecting shoulders or shields which serve to cover thelooking holes formed in the base and thereby effectively block thepassage of the are through the holes formed in the base.

In the accompanying drawing Fig. 1 shows a three-pole electric switchmounted in an inclosing casing and provided with the im proved form ofarc barriers, one of the barriers being removed and certain parts of theswitch mechanism and casing being broken away to reveal the details ofconstruction. Figs. 2 and 3 are front and reverse perspective views ofthe unitary moulded arc barrier showing the detailed form of the lockingkeys and the shoulders formed thereon.

As shown in Fig. 1, the three-pole switch is of the improved typedescribed and claimed in the copending patent application of Louis J.Weber, Serial No. 241,950, filed December 22, 1927, and assigned to theassignee of my present invention, patented December 31, 1929, No.1,742,109. The three-pole switch mechanism is mounted upon the base 10which, in turn, is mounted within the inclosing casing 11. Each pole ofthe three-pole switch mechanism consists of a set of spacedapartstationary contacts 12 which are mounted directly upon the base 10and a cooperating bridging contact 13 which is yieldingly mounted upon amovable switch arm 14. The three movable switch arms are fixedly securedto an operating member 15 which is rotatably supported in the bearings16 and 17 In order to prevent arcing between the adj acent poles of theswitch, provision is made for mounting an arc barrier 20 on the base 10between the adjacent sets of stationary contacts 12. The are barriers 20are formed of good arc-resisting material such as, for example, mouldedasbestos compound, and are of suitable dimensions to eiiectively is0late the arcs occurring at the adjacent poles of the switch.

In accordance with the present invention, each of the are barriers 20 isarranged to be removably mounted on the base 10 of the switch mechanismso as to be readily removable from the front of the panel without theuse of tools. This is accomplished by providing a pair of keyhole shapedopenings 21 and 22 in the base 10 for each arc barrier. The are barriersin turn are provided on one side with a pair of projecting locking keys23 and 24 adapted to be received in and interlocked with the openings 21and 22. As more clearly shown in Figs. 2 and 3, the locking keys 23 and24 have projections 25 on either side so as to interlock with the narrowportions 26 of the key-hole shaped openings 21 and 22. The projections25, however, are of suitable dimensions to pass through the enlargedportion 27 of the key-hole shaped openings in the base.

It will be evident that after passing the shoulders 25 through theenlarged portion of the key-hole openings, the barrier may be sliddownward to bring the projections 25 into interlocking engagement withthe narrow portions of the openings and thereby firmly secure each ofthe arc barriers in operative position on the base 10 between the polesof the switch. In order to insure that the arc barriers are notaccidently displaced from the interlocked position by extraneousvibration or during handling of the switch a spring 28 preferably islocated at one side of the key-hole shaped openings in the base 10 so asto frictionally engage with the locking key on the arc barrier. It willbe observed in Fig. 1 that the upper key-hole shaped openings 22 in thebase 10 are not closed at the top. It will be evident, however, that incase the base 10 were extended the key-hole shaped openings 22 would beof substantially the same shape as the openngs 21, except for theprovision of the looking spring 28, the mounting of which requires anarrow slot 29 extending from the narrow portion of the opening 22.

In order to prevent the are passing through the enlarged portions of thelocking open- 1ngs in the base 10 when the arc barriers are mounted inoperative position, suitable meaese shoulders 30 and 31 are provided oneither side of the barrier 20 of suflicient width to cover completelyall the openings in the base. The shoulder 31 extends across the fullwidth of the arc barrier so as to cover the slot 29, as well as theright hand edge of the enlarged portion of openings 21 and 22. Theshoulder 30 serves to cover the left hand edge ofthe enlar ed opening21.

With the ase 10 mounted within the inclosing casing 11 and the arcbarrier 20 in operative position between thepoles of the switchmechanism as indicated in Fig. 1, the arc barriers may be readilyremoved by sliding the barrier bodily upward until the interlockingshoulders 25 are moved out of engagement with the narrow portion of thekeyhole openings. Thereupon the barrier 20 may be freely withdrawn outof engagement with the base 10. To replace the barrier it is onlynecessary to reverse the operations just described.

Thus it will be seen that the present inventionprovides an arc barrierconstruction that permits the barriers to be mounted and demounted atwill and without the use of any tools. In addition, the barriers beingformed as a unitary structure of arc resisting material without anymetallic fastenings required for their support, there is full insulationbetween theadj acent poles of the switch which efiectively isolates thearcs appearing at each of the poles.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In a circuit interrupter, the combination of a base having arcingcontacts mounted thereon and having key-hole-shaped openings formedtherein and an arc barrier having projecting keys operable into and outof interlocking engagement with the open-' ings in the base'uponpredetermined relative movement of the barrier with respect to saidbase.

2. In a circuit interrupter, the combination of a base having arcingcontacts mounted thereon and having key-hole-shaped openings formedtherein and an arc barrier having projecting keys operable into and outof interlocking engagement with the openings in the base uponpredetermined relative movement of the barrier with respect to said baseand having shoulders for covering the enlarged portions of the key-holeshaped openings in the base when the barrier is mounted in operativeposition.

3. In a circuit interrupter, the combination of a base having arcingcontacts mounted thereon and having key-hole shaped openings formedtherein, an arc barrier having projecting keys operable into and out ofinterlocking engagement with the openings in the base upon predeterminedrelative movement of the barrier with respect to said base, and aresilient locking member for maintaining the arc barrier in interlockedengagement with the base.

4. A multipole electric switch comprising a base having a plurality ofswitch contacts in spaced alignment thereon and having keyhole-shapedopenings formed in the base between said contacts, a plurality of arcbarriers for mounting in said openings, said barriers each havingprojecting keys formed on one edge thereof and operable into and out ofinterlocking engagement with the openings in the base upon predeterminedrelative movement of the barrier with respect to said base and havingshoulders for covering the corresponding openings in the base when thebarrier is mounted in operative position.

In witness whereof, I have hereunto set my hand this 3rd day ofFebruary, 1928.

JOSEPH W. UWENS.

